Polymerization process employing transition metal compounds as catalysts



United States Patent O 3,370,041 POLYMERIZATION PROCESS EMPLOYING TRAN-SITION METAL COMPOUNDS AS CATALYSTS Walter A. Komicker, Raleigh, N.C.,Erhard P. Benzmg, Kirkwood, Mo., and Eli Perry, Raleigh, N.C., assignorsto Monsanto Company, St. Louis, Mo., a corporation of Delaware NoDrawing. Original application Feb. 25, 1063, Ser. No.

260,830. Divided and this application June 17, 1966, Ser. No. 574,844

12 Claims. (Cl. 260-67) This application is a division of copendingapplication Serial No. 260,830, filed February 25, 1963.

The present invention relates to transition metal compounds, a processpreparing these compounds, and the use of these compounds aspolymerization catalysts.

The transition metal compounds of the invention have the followinggeneral formula )a( )b( 4)c d In this formula R R and R are identical ordifferent aliphatic, cycloaliphatic, araliphatic or aromatic hydrocarbonradicals or heterocyclic radicals. R and R taken together can also forma heterocyclic ring. M is a transition metal or metal oxide of theGroups IVa, Va, VIa, VlIa and VIII of the Mendeleetf periodicclassification. Identical or different organic ligands can be linked bytheir radicals R or by a common radical R. The letters a, b, c and d arezero or integers with the letter at possibly till to be divided by thebase valency of the acid anion X, and a+b+c+d correspond to theeffective valency of the metal or metal oxide radical M in the compoundsof the above formula. Preferably the radicals R are each free ofnon-benzenoid unsaturation, i.e. olefinic or acetylenic unsaturation,and each have not more than 18 carbon atoms, more preferably not morethan 8 carbon atoms. Preferred radicals R are saturated aliphatichydrocarbon radicalseither cyclic or open chain; however, as will beseen in the more detailed description of the invention and as has beensuggested above the radicals R can also be araliphatic, aromatic,heterocyclic hydrocarbon radicals, the heterocyclic radicals havingoxygen, sulfur and nitrogen heteroatoms, or R and R taken together with.the nitrogen to which they are attached can form heterocyclichydrocarbon radicals having not more than 18 carbon atoms, preferablynot more than 8 carbon atoms.

The following derivatives of transition metals to be considered here.have .not yet been .known and are novel:

1. Derivatives having as ligands exclusively secondary amine radicals,except the respective derivatives of the highest valent titanium andzirconium.

2. Derivatives having at least two ligands which differ with regard totheir heteroatom bound to the metal and.

ice

which are selected from alkoxyl, secondary amine radicals and EH 3.Derivatives having as ligands alkoxyl, secondary amine radicals and/ orBH, in addition to acid anions, except alkoxyl derivatives of thetransition metal chlorides of Groups IVa and Va of the periodicclassification, and BH, containing derivatives of the titanium chloride.

For this reason the formula set forth is valid with the restriction thatcannot be admitted the R 0 ligands solely or together only with halogenon a transition metal, the R R N ligands solely on the highest valenttitanium or zirconium, and the EH ligands solely or together only withhalogen on titanium.

Examples of transition metals or transition metal oxides to be met withthe products of invention are: Ti, TiO, Zr, ZrO, Zr O V, V 0, Nb, NbO,Cr, CIO M0, M00, M00 W, WO, W0 Mn, Fe, Ta, Co, Ni, etc.

Examples of acid anions are: Halogen, R050 S0 (RO )PO ROPO P0 N0 C10 CN,SCN, CHgCOO, CH COCHCOCH etc.

The secondary amine derivatives can be prepared by reacting alkalisalts, Grignard compounds etc. of secondary amines with salts,preferably halides, of transition metals or transition metal oxides.According to the stoichiometric proportion of the reactants used, thereare formed products containing as ligands either exclusively amidegroups or amide groups and acid anions; by reacting, for example,vanadiumoxytrichloride and lithiumdimethylamide this reaction isillustrated by the following equation:

Secondary amines suitable for the reaction are, for example,dimethylamine, diethylamine, dipropylamine,, dibutylamine,methylcyclohexylarnine, dicyclohexylamine, methylbenzylamine,dibenzylamine, methylaniline, propylp-toludine, diphenylamine,pyrroiidine, piperidine, morpholine etc.; moreover also biandmulti-valent secondary amines, like 1,2-bis-(methylamino)-ethane, 1,3bis (ethylamino) propane, 1,2 bis (n1ethylamino)-propane, 1,6 bis(methylarnino) hexane, 1,4-bis-(methylamino)-benzene,1,2-diphenylguanidin, 1,2-dipropylhydrazine,tris-(methylamino)-s-triazine etc.

In the same manner are obtained by reacting alkalialcoholates,-phenolates, or -boranates the corresponding derivatives.

It is possible to obtain also multi-substituted transition metalcompounds with ditferent organic ligands or containing organic ligandsand EH i.e. all ligands to be considered here can be combined. In suchcases one reacts, or example, a transition metal halide eithersimultaneously or stepwise with at least two salts which are able togive off different ligands. Mixed ligands containing transition metalcompounds are particularly useful as catalysts and also for otherpurposes, because of the varied firmness of attachment of their ligands.

For the manufacture of the novel products according to this directmethod one proceeds thus, that the metal compound of the ligand to beintroduced is prepared in usual manner in an appropriate solventfirstly, for example, from dialkylamines by means of butyllithium,Grignard agents etc., from diarylamines, alcohols and phenols by meansof sodium, potassium, lithiumhydride etc. and from borontrifluoride bymeans of lithiumhydride a conveniently dissolved transition metal halideor -oxyhalide and, if necessary, heated for some time. Owing to thesensibility of the startingand end-products, any moisture must beexcluded from the reaction mixture. In the stepwise synthesis it makesno difference which organic substituents are introduced at first, sinceacid anions like, for example, chlorine are easier exchanged thanorganic ligands already present. On the contrary, the EH ligand mustalways be introduced last, since it would be altered by the reactingamides, alcoholates and phenolates. Of course, instead of two differentorganic ligands, for example, alkoxide and secondary amide, there can beintroduced one organic ligand possessing two respective functionalgroups, for example, a hydroxyl and a sec ondary amine group which bothbecome attached to the same transition metal atom or, dpending on thecircumstances, to two different transition metal atoms. Such compoundscorrespond to the following types:

Ti \R5 N It.

Compounds of type Ill are obtained, when transition metal compoundshaving still one acid anion attached to the metal and capable of beingsubstituted, are reacted with salts or Grignard compounds respectivelywhich transfer radicals of bifunctional ligands, or without regard tothe number of acid anions present, when the hydrocarbon radical R owingto steric properties hinders the formation of a compound of the firsttype. Bifunctional substituents showing identical groups have alreadybeen enumerated above and such showing varied groups which come intoquestion are aminoalcohols and aminophenols.

One can quite generally exchange organic ligands partially for acidanions by treating the transition metal compounds with a calculatedamount of water-free acid, such as hydrohalide, carboxylic acid etc.

A further method for preparing organic substituted transition metalhalides or -oxyhalides is based on the fact, that by reaction ofchlorine, bromine or iodine with the secondary amide groups these canentirely or partially be replaced. This method has practical importanceespecially for the manufacture of the less easily available bromides andiodides.

Finally, the easier available chlorides can be converted into othersalts by double reaction with salts of other acids, for example, KCN,NaCNS, sodium oxalate, sodium acetylacetonate etc.

A further method for the preparation of transition metal compounds whichpossess a combination of the organic ligands, 81-1., and acid anionstaken in consideration here is based on the transfer of one or moreligands from one compound to the other. This mutual exchange ofsubstituents, further called coproportionation, proceeds with compoundswhich are similar with respect to the metal or metal oxide, according asare used two or even three compounds.

The composition of the endproducts formed by the coproportionation isdirected on one hand by the stoichiometric ratio of the reactants and onthe other hand also by the stickiness of the ligands. Only in an idealcase as, for example, in the coproportionation oftetrakis-(dimethylamido)-titanium and tetrakis-(iso-propoxy) titanium,one obtains practically quantitatively the desired uniformbis-(dimethylamido)-bis-(iso-propoxy) titanium according to the scheme:

In other cases there can be formed mixtures of various endproducts. Itis understood that also transition metal compounds can becoproportionated which have different ligands and/ or differenttransition metals and/ or have a transition metal and a transition metaloxide. When, for example, tetrakis-(dimethylamido)-titanium andtetrakis- (iso-propoxy)-zirconium are coproportionated according to thescheme mentioned above, a mixture consisting of about equal parts ofbis-(dimethylamido) bis (iso-propoxy)-titanium and bis-(dimethylamido)bis-(iso-propoxy)-zirconium is obtained. It is intelligible, that alsothe coproportionation with transition metal compounds which havenon-identical metals will only occur in the ideal case regularly andwill depend on the equilibrium which is established in the reactionmixture under the given conditi-ons, thereby this equilibrium canpossibly be shifted in a defined direction by removing one of the formedreaction products. Although the separation of such a mixture intoanalytically pure products is hard to realize, it can however bedemonstrated that a transfer of ligands according to the process ofinvention occurs also between different transition metals. When, forexample, dimethylamido-titanium-trichloride, which in contrast to allother compounds of the same chloride class is scarcely soluble inbenzene, is heated with, for example, tetrakis-(dimethylamidoI-zircon orwith tris-(dimethylamido)-vanadiumoxide in anhydrous benzene, it goesgradually into solution, since bis-(dimethylamido)-titanium-dichlorideis formed which is easily soluble in benzene.

Often, it may be advantageous to coproportionate easier and cheaperavailable metal compounds, such as aluminium-alkoxylate, tin-amides etc.with corresponding transition metal compounds. Thereby, it is formed amixture of identical or closely related derivatives of the transitionmetal and the aluminum or tin. Such mixtures as well as all the othermixtures herein described can be used without separation aspolymerization catalysts for alphaolefins, acrylate, styrene,acrylonitrile etc.

The coproportionation is carried out in simple manner by heatingtogether at least two different derivatives of transition metals, orpossibly together with derivatives of aluminium or tin or any suitablemetal or element, in the convenient proportions in a solvent underexclusion of humidity and, if necessary, also under exclusion of oxygen.A catalyst may be added if desired.

The isolation of the various reaction products obtained according to themanufacturing processes described herein, can be done after removal ofthe solvent in usual manner by crystallization, sublimation and incertain cases also by distillation in vacuo. But the arising solution ormixture respectively can also be used directly.

The organic transition metal compounds containing the ligands mentioned,especially secondary amine radicals or EH show the noteworthy propertyto split off the ligands on heating, thereby a lower valent transitioncompound is formed. This decomposition occurs with, for example,alkoxy-titanium-tn'boranate and with tetrakis-(dimethyl amido)-titaniumaccording to the following equations:

The decomposition occurs particularly easy with compounds having atleast two BH, or secondary amide ligands. In the latter case is formedat 105 C./1l mm. almost quantitatively tris-(dimethylamido)-titaniumbesides tetramethylhydrazine.

EXAMPLE 1 Dimethylamido titanium-zrichloride 7.4 ml. (0.067 mole) oftitanium tetrachloride are added under nitrogen to a solution of 5 g.(0.022 mole) of tetrakls-(dimethylamido)-titanium in ml. dry benacne- Te re ion. mi e i refl ed f r one hour. The

insoluble product is obtained by filtration, Washed with benzene anddried. Yield: 16 g. (96% of the theory). Olive-green powder, extremelysensitive to moisture.

C H NCl Ti (198.4). Titration with 0.1 N sodium hydroxide: 173 mg.correspond to 17.50 m1. Calculated: 17.44 ml.

EXAMPLE 2 Tris-(N-methylanilido)-titanium-chloride 0.36 ml. (0.0033mole) of titanium tetrachloride is added under nitrogen to a solution of4.7 g. (0.009 mole) tetrakis-(N-methylanilido)-titanium in 50 ml. drybenzene. The reaction mixture is refluxed for one hour. The insolubleproduct is washed with dry petroleum ether and dried. Yield: 3.0 g. (56%of the theory). Brown powder, sensitive to moisture.

Analysis.C H N TiCl. Percent calculated: N-methylaniline, 52.8; C1, 8.8.Found: N-methylaniline, 51.5; C1, 8.7.

EXAMPLE 3 Tris( diphenylamido) -titanium-chlride EXAMPLE 4 Di phenylamia'o-titani um-trich loride 1.3 ml. (0.012 mole) of titaniumtetrachloride is added under nitrogen to a solution of 2.9 g. (0.0004mole) tetrakis(diphenylamido)-titanium in 50 ml. dry benzene. Thereaction mixture is refluxed for one hour. The solvent is evaporatedunder vacuum. Petroleum ether is added to the sticky red residue whichis then kept in a deep freeze. The solid product is washed withpetroleum ether and dried. Yield: 3.8 g. (65% of the theory).

Analysis.C H NTiCl Percent calculated: C, 44.70; H, 3.13; N, 4.35; Ti,14.88; Cl, 33.0. Found: C, 44.37; H, 3.45; N, 4.01; Ti, 14.44; Cl,33.52.

EXAMPLE 5 T ris-(dimethylamido)-titanium-chl0ride A solution of 10.8 g.(0.24 mole) of dimethylamine in 50 ml. diethylether is added to asolution of 15.4 g. (0.24 mole) of n-butyllithium in 150 ml. dry etherat such a rate that the ether boils gently. After all dimethylamine hasbeen introduced, a solution of 8.8 ml. (0.08 mole) titaniumtetrachloride in 25 ml. dry benzene is added within minutes. The mixtureis refluxed for 3 hours. The lithium chloride precipitates. The solvent'is evaporated to dryness. The brown residue is sublimed under vacuum.Yield: 2.9 g. (17% of the theory), yellow crystals, sublime at 4060 C./0.05 mm. Hg.

The corresponding compounds of zirconium and hafnium are prepared in thesame way as indicated in the examples mentioned above. The samereactions are valid for the preparation of transition metal mercaptidesand for their halides.

EXAMPLE 6 Bis-(dimethylamido)-bis(is0-pr0p0xy)titanium A mixture of 11.2g. (0.05 mole) tetrakis-(dimethylamido)-titanium and 14.2 g. (0.05 mole)tetrakis(isopropoxy)-titanium is refluxed for one hour in benzene. Thesolvent is removed under reduced pressure, distillation under vacuumyields a light-yellow liquid. Yield: 24.2 g. of the theory) B.P.=60C./0.02 mm. Hg. (The boiling points of the starting materials arerespectively: 54 C./0.1 mm. Hg. and 48 C./0.004 mm. Hg.).

Analysis.-C H ,-O N Ti (254.2). Percent calculated: C, 47.3; H, 10.3; N,11.0. Found: C, 47.1; H, 10.3; N, 10.7.

Properties: Extremely sensitive to moisture.

EXAMPLE 7 T risdimethy la'mido -z'sop r0 poxy-titanium Analysis.-C H ONTi (239.2). Percent calculated: C, 45.2; H, 10.5; N, 18.0. Found: C,45.1; H, 10.4; N, 17.9.

EXAMPLE 8 Tris- (dimethylamido)-vanadium-oxide To a solution of 12.8 g.of lithiumdirnethylamide (0.25 mole) in 200 ml. of anhydrousdiethylether is added a solution of 14.4 g. of vanadiumoxytrichloride(0.083 mole) in 150 ml. of anhydrous diethylether within half an hourunder cooling. After the addition is complete, the dark solution isstirred for one hour at room temperature. The precipitated inorganicsalts are removed by filtration under exclusion of moisture. Thefiltered solution is evaporated to dryness under vacuum. The residue(about 15 g.) is sublimed under high vacuum (10 mm.). Yield: 4 g. ofdeep red, almost black crystals (=25% of theory for VO(NMe M.P. 40 C.

Analysis.C H ON V (M 199.2). Percent calculated: C, 36.2; H, 9.1; N,21.1; V, 25.6. Found: C, 36.9; H, 9.7; N, 20.8; V, 24.9.

Significantly the same results are obtained when hexane is used insteadof diethylether.

EXAMPLE 9 T ris- (diethylam-ia'o -vanad i um-oxid 2 It is proceeded asindicated in Example 8, but hexane is used as a solvent. From 39.0 g. oflithiumdiethylamide (0.5 mole) and 28 g. of vanadiumoxytrichloride(0.163 mole) are yielded after evaporation to dryness 50g. of a deep redresidue. Distillation under high vacuum yields a red mobile liquid.Yield: 7 g. (=15% of theory for VO(NEt B.P. C./0.3 mm.

Analysis.C H N OV (M 283.3). Percent calculated: C, 50.8; H, 10.7; N,14.8; V, 18.0. Found: C, 49.9; H, 9.9; N, 14.5;V, 17.7.

EXAMPLE 10 Bis- (diethylamido -vanadz'um0xychl0ria'e To a solution of3.4 g. of tris-(diethylamio)-vanadiumoxide (0.012 mole) in 20 ml. ofanhydrous benzene are added under nitrogen 0.57 mlnofvanadiumoxytrichloride (0.006 mole). An exothermic reaction occurs. Theintensively red colored solution isstirred at room temperature during 1hour. Then, the benzene is evaporated under reduced pressure, therebythetemperature must not exceed 60 C. The residue is a dark brown-redsolid product which contains the calculated amount of chlorine anddiethylamide bound to V0. Yield: Quantitative. Only a little part of thecrude product can be distilled in high vacuum without decomposition. Themain part endures a thermic decomposition, thereby a compound of threevalent vanadium is formed under evolution of easily volatile nitrogenbases.

EXAMPLE 11 T ris-(dimethylamido)-tizanium-br0hydride 2.8 g. oflithiumborohydride (LiBI-LQ (0.13 mole) dissolved in 60 ml. of drytetrahydroiurane are added under nitrogen to a solution of 21.6 g. oftris-(dimethylamido)- titanium-chloride (0.10 mole; B.P. 80 C./0.001mm.) in 100 ml. of tetrahydrofurane. The solution is refluxed for onehour. After that time the solvent is evaporated under reduced pressure.Distillation of the residue under high vacuum yields yellow crystals.Yield: 11.3 g. (=58% of the theory for [(CH N] TiBH B.P. 60 C./0.0l mm;M.P. 50 C.

Analysis.-C H N BTi (M 195.0). Percent calculated: C, 37.0; H, 11.4; N,21.6; B, 5.5; Ti, 24.6. Found: C, 36.7; H, 10.4; N, 20.5; B, 6.7; Ti,25.7.

EXAMPLE 12 Dimethylamido-titanium Tris (dimethyla-mido) titaniumborohydride (4.0 g.=0.021 mole) is heated under vacuum in a glass bulb.At 70 C. the molten yellow substance turns black. At the same time theadduct of dimethyla-mine with borine and volatile nitrogen bases areevolved and condense in a cooling trap cooled with liquid nitrogen.After the flask has been maintained for two hours at 200 C. a finely divided black powder is obtained. Yield: 2.0 g., almost quantitative basedon Ti[N(CH Analysis.--C H NTi. Percent calculated: C, 26.1; H, 6.5; N,15.2; Ti, 52.2. Found: C, 23.86; H, 4.62; N, 18.24; Ti, 47.93.

These results correspond to C H NTi contaminated with 0.2 atoms of boronand 0.3 atoms of nitrogen.

Properties: This compound of low valency titanium is extremely easy tooxidize. In contact with air it ignites spontaneously. It reactsviolently with water, yielding hydrogen, dimethylamine and Ti(OH EXAMPLE13 This example describes the polymerization of acryloa catalyst of theinvention. The reactor flask is heated at 150 C. and cooled undernitrogen to prepare it for the polymerization experiment. To the flaskis added ml. of toluene purified by fractionation and dried over sodium.Then 2.9 ml. of acrylonitrile is added to the reaction flask and theflask and contents are cooled to 76 C. At this 0.34 ml. of the catalystis added slowly to the flask. A rapid reaction occurs. After 4 hours 3ml. of methanol is added to the reaction mixture and the reactionmixture is transferred to a large volume of methanol to precipitate thepolymer. The recovered crude polymer is treated with dimethylformarnideto remove catalyst residues and the polymer is separated from thedimethylformamide by filtration and dried under vacuum. The polymeryield is 2.2 g. (90%) having a molecular weight of about 30,000.Compared to a normal free-radical produced, polyacrylonitrile thepolymer has a narrow molecular weight distribution and shows severalextra lines in X-ray analysis (indicating greater molecular order).

trile using a modified catalyst of the invention, namely Ti[N(CH (I) andn-tributylphosphine (II). As in Example 13, the reactor is prepared byheating at 150 C; and cooling under nitrogen. To the reactor is added 31ml. of water-free toluene, 0.47 ml. of (I) and 1.0 ml. of (II) withstirring. The temperature of the flask and contents is adjusted to 25C., and 9 ml. of acrylonitrile is added to the flask over a period of 10minutes. The reaction is allowed to continue for 15 hours and thepolymer is precipitated by pouring the reaction mixture into 800 ml. ofmethanol. The crude polymer is then filtered from the methanol, driedand subjected to additional purification steps which involved treatingwith dimethylformamide, filtering to separate the polymer, precipitatingthe polymer from methanol, filtering to remove further methanol anddrying under vacuum. Conversion is 98% to a polymer having a molecularweight of about 30,000. Control experiments using 5 times as much ofeach of the above catalysts individually give only 60% conversion topolymer showing the synergistic effect of the mixed catalysts.

EXAMPLE 15 This example describes the polymerization af acrylonitrileusing yet another catalyst of the invention, namely VO[N(CH Again thereactor is prepared by heating at 150 C. and cooling under nitrogen. Tothe reactor is added 5.8 ml. of purified acrylonitrile and 20 ml. ofwater-free heptane. The temperature of the reactor charge is maintainedat 20 C. while stirring and adding 0.76 ml. of catalyst dropwise. Thereaction is allowed to continue for hours after which time the polymeris recovered by precipitation from methanol. The polymer is subjected tousual purification techniques as described in Example 14 above and it isdetermined that conversion is 91% to a polymer having a molecular weightof about 30,000. This compares with 0% conversion for a controlexperiment run under the same conditions except in the absence ofcatalysts.

The transition metal amides and amides-alkoxides, such as, for example,Ti(NMe Ti(OR) (NMe etc. are strong catalysts for acrylonitrilepolymerization over the temperature range of -100 to 100 C. with thepreferred range being 76 to +22 C. Conversion is highest at the lowesttemperatures. These catalysts are also useful for polymerizingmethacrylonitrile under like conditions. The degree of polymerization ofthe polymer is inversely related to the temperature. The solvent isimportant in determining the degree of polymerization.Dirnethylformamide gives the lowest degrees of polymerization.Generally, the polymers made with Ti(NR are easily soluble indimethylformamide up to very high degrees of polymerization. This resultsuggests that the polymer is linear and of narrow molecular weightdistribution. The catalytic activity varies with the solvent, decreasingin the series heptane toluene tetrahydrofuran dimethylformamide. Theactivation energy of the polymerization rate has a small negative valuefor both the Ti(NMe and Ti(NMe (OR) catalysts. The effect ofdimethylformamide in terminating active centers which is apparent usingTi(NR is enhanced with Ti(RO) (NR The molecular weight has a largenegative activation energy in dimethylformamide and heptane, but isalmost Zero in tetrahydrofuran and toluene for the Ti(OR) (NMe catalyst.When using the Ti(NR the activation energy for the molecular weight isnegative and large for all solvents. Neither Ti(OR) nor TiCl arecatalysts for acrylonitrile polymerization at 76 and at +25 C. Thus, thestrength and type of the catalysis can be varied by systematically andgradually varying the nature of the substituent groups (e.g. Cl Ti(NR toTi(NR or (RO TKNR to Ti(NR Other transition metal derivatives ortransition metal oxide derivatives have similar properties. VO(NEtlikewise is a strong catalyst with an activation energy of 3-4 kcal./ g.mole. The molecular weight is higher at lower temperatures, but thisvariation may be due to a rate effect. In general, in the case of amidederivatives of Ti and V, ionic catalysis is more easily obtained whenthe monomer contains an electron rich group. Solvent of high dielectricconstants and low temperatures favor the ionic mechanism. With mixedcatalysts of (n-butyl) and Ti(NR as high conversions are obtained with0.01 of the normal amount of Ti(NR- plus 0.1 to 0.2 of the normal amountof phosphine as with the normal amounts of either catalyst usedseparately. Thus, a synergistic effect can be claimed by using organictransition metal compounds plus triorgano-phosphines.

EXAMPLE 16 This example describes some styrene polymerizationexperiments using catalysts of the invention which are as follows:Ti[N(CH (I) and Ti [N(CH (II). The three reaction flasks were preparedfor the three experiments of this example by heating the flasks at 150C. and cooling under nitrogen. To one of the flasks is added a smallamount of catalyst (I), to a second flask is added the catalyst (II) inabout an equivalent amount to the amount added to the first flask, andto the third flask is added /2 equivalent of (I) and /2 equivalent of(II). All three flasks are maintained at 25 C. with agitation and 20 ml.of purified styrene is added to each flask over a period of 5 minutes.After 167 hours the reaction masses are poured into 500 ml. of methanoland the catalyst residues are removed by filtering and redissolving. Theyields of polymer from the first two flasks are low on the order ofabout whereas, in the case of the last flask having the mixed catalystthe yield is more than twice as large. A control experiment Withoutcatalyst shows a conversion of only 0.3%. Thus it is seen that all thecatalysts are effective and the combination of the 2 and 4 valentcatalysts are more effective than either the 2 or 4 valent catalyststaken alone.

T1(NMC2)4, and Cl Ti(NMe are weak free radical catalysts for styrenewith gradually diminishing strength in the above order, allowing achoice of catalyst for a particular type of reaction. All are soluble inthe reaction media. The catalysts are also useful for polymerizingot-rnethyl styrene. With Ti(NMe at C. a molecular weight (MW) of about100,000 is obtained, giving a chain transfer constant for the catalystof about 0.05. A wide variety of solvents, such as toluene, Decalin,dioxane, heptane, tetnahydrofuran, dimethylformamide, etc., can be used,which act only as inert diluents. Dimethylformamide forms an insolublecomplex with the titanium compounds. Similar complexes would be expectedusing dioxane and tetrahydrofuran. If they do form, they are soluble.These complexes do not appear to effect the catalytic activity of thetitanium compounds. There are no significant differences in thepolymerization rates when substituting the NMe for the NEt radicals,both being radicals of. strongly basic secondary amines. But, forexample, the substitution for a diphenylamine radical decreases theactivity. Ti(OR) is not a catalyst for styrene, but

is found to be aweak catalyst approaching the Ti(NMe strength. There isa series of compounds having gradually decreased strength from Ti(NMe toTMNM Z) (0103 The Ti(OR) (NMe possesses a greater storage stability thanthe other titanium compounds of the same series. The order of magnitudeof the chain transfer constant for the catalysts at 60 C. is about0.022. Ti(NMe BH is also a weak catalyst for the polymerization ofstyrene. However this catalyst is weaker than Ti(NMe and correspondsmore to the catalytic action of Ti(NMe Cl and Ti(NMe Cl The analogs ofother transition metals or transition metal oxides display the sameproperties as catalysts for styrene. Likewise,

10 VO(NEt at +25 C. has a rate of conversion of 0.03%/h. The styrenepolymers obtained by the use of these catalysts have normal softeningpoints. However, the largest Bragg X-ray spacing is smaller than innormal free radical polymer, so that it is concluded that the chainorder is different than in normal polymer and crystallinity may beachieved.

EXAMPLE 17 This example describes the polymerization of methylmethac-rylate (NM) using the catalyst Ti[N(CH To a reactor heated at C.and cooled under nitrogen are added 12 ml. of water-free heptane and 1.2ml. of catalysts. The temperature of the flask and contents is adjustedto -30 C. and 8 ml. of methyl methacrylate is added with stirring over aperiod of two minutes. After 36 hours the reaction mass is treated with3 ml. of methyl alcohol and 4 drops of water. After 1 hour the mass isprecipitated in 500 ml. of petroleum ether, filtered and freed ofcatalyst by redissolving in benzene, filtering, precipitating inpetroleum ether, and the polymer vacuum dried. Yield of polymer is 75%of 200,000 molecular weight versus no polymer for a control experimentwithout the catalyst. When the polymer of this experiment is compared toconventional free-radical produced polymer, the softening point is 40 C.higher and the material of this example crystallizes from 4-heptanone;whereas, the free-radical polymer does not.

EXAMPLE 18 This example describes the polymerization of methylmethacrylate using 3)2]z( a)z catalyst of the invention. To a reactorheated at 150 C. and cooled under nitrogen is added 20 ml. of water-freeand pure methyl methacrylate. The reactor and contents are adjusted to atemperature of 25 C. and 1.3 rnl. of catalyst is added dropwise withagitation. The polymer is treated to purify it and isolate it as inExample 17. The product has a molecular weight of about 500,000 andshows a crystalline X-ray diagram when crystallized from heptanone. Acontrol experiment yields no polymer. For the polymer of this example,the X-ray spacings determine from a powder diagram are: 13 A. sharp, 7A. sharp, 5.2 A. sharp, 3.1 and 2.3 A. diffuse. A free-radical polymerhas X-ray spacings as follows: 6.0, 2.9 and 2.1 A. all diffuse.

EXAMPLE 19 This example describes the polymerization of methylmethacrylate using the VO[N(C H catalyst of the invention. The reactionflask is prepared was in Example 17. To the flask is added 5 ml. ofmethyl methacrylate and 15 ml. of heptane and the temperature ismaintained at 25 C. Then 0.6 ml. of catalyst is added with stirring andthe reaction is allowed to proceed for 164 hours. The product is workedup and purified as in Example 17. The product crystallize-s fromheptanone and has a softening point of C. Also the product is isotacticas evidenced by the lack of absorption bands in the infrared at 9.4 and10.9 microns. Without catalyst no polymer is obtained. Free radicalpolymer does not have the properties mentioned above.

EXAMPLE 20 This example describes the polymerization of methylmethacrylate using the same catalyst as was used in Exple 19. Theprocedure in this example is the same as in Example 19 except thatdimethyl formamide is substituted for the heptane. The yield of polymeris 70%.

EXAMPLE 21 This example describes the preparation of a copolymer ofmethyl methacrylate and styrene using the M1. methyl methacrylate 5 Ml.styrenenfl' 5 5 Ml. catalyst 0. 6 0. 6 Hrs. reaction 166 164 A smallyield of polymer, 2%, is obtained from flask A and this is a truecopolymer 50-50 of styrene and methyl methacrylate The product fromflask B is obtained in 19% yield and is pure polymethyl methacrylatecontaining no styrene and 43,000 molecular weight.

While TiCl and THOR), are not catalysts for methyl methacrylate, thetransition metal compounds of invention show strong catalytic activity.The initiation by, for example, Ti(NR is anionic, at least 25 C. Athigher temperatures (+25 C.), initiation may be free radical. Thecatalysts of the invention are also very useful for polymerizing alkylacrylates. The rate normally is greater at -25 C. than at higher orlower temperatures and varies greatly with the specific solvent used.The molecular Weight is not a function of the monomer concentration. Itis affected, as well as the rate, by traces of water. When water wasadded purposely to a reaction mixture with a concentration of Ti(NMe of25x moles/l. (l00 l0 equivalent/1.), as little as l8X10 equivalent/l. ofwater reduced the rate and molecular Weight significantly. The rate ofinitiation is not instant-aneous since the same conversions andmolecular Weights are obtained irrespective of the order in which thepure reactants are mixed. It was found that the effect of impurities onthe molecular weight and rate is smaller when the catalyst is addedfirst. Apparently, a minimum amount of catalyst is then required beforeappreciable polymerization occurs. The presence of toluene has a markedeffect, leading to higher conversions and polymers with lessenedsolubility in benzene. The presence of some very small molecules wasshown. The overall activation energy (E) of the polymerization rateusing Ti(NMe is ca 3.2 kca1./g. mole without solvent over thetemperature range of 25 to 60 C. With toluene present, E is 4.6 over thesame temperature range. At 76 to -30 C. E, is positive. Ti(NPh is a muchweaker catalyst than Ti(NME Ti(OR) (N R is a much weaker catalyst thanTi(NR and gives a molecular weight which is much higher, also. Thepolymer obtained without the use of solvent using Ti(OR) (NMe catalystcrystallizes from heptanone. The related knowledge that the stickingtemperature depends on a factor other than the molecular Weight (MW)suggests that the crystallization from heptanone also depends on achange in structure and is not merely an effect of these high MWs. Manyof the methyl methacrylate polymers produced by the transition metalcompounds of invention are definitely different in structure from freeradical polymer. The sticking temperature varies greatly from 120 to 220C. while with free radical polymer the sticking temperature is normallyless than 170 C. even for polymer of very high MW. Polymer of low MW canprecipitate from 4 heptanone while polymer of high MW can remain solublei.e. polymers can be made with differences in solubility in heptanone(i.e. crystallinity) for a given MW. The softening point can vary widelyfor the same MW, and the material crystallized from heptanone may or maynot have a higher softening point than the material left in solution.Abnormal polymer is favored by low temperatures and the use of solvent.With other transition metal or transition metal oxide compounds, like,for example, VO(NR similar results are obtained. All types of alkylmethacrylates and acrylates are polymerizable by the catalysts of theinvention, e.g. methyl methacrylate, ethyl methacrylate, n-propylmethacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2- ethylhexylmethacrylate, lauryl methac-rylate, oxo-tridecyl, methacrylate, Lorolmethacrylate, tallow methacrylate, etc., and mixtures of methacrylates,and the corresponding acrylates. Polymers of the methacrylates andacrylates mixed with other monomers can of course be made as isillustrated in Example 21 above which describes polymerizing methylmethacrylate styrene. Preferred acrylates and methacrylates are thosehaving alkyl of 18 carbon atoms or less. Tallow methacrylate is amixture of about 33% by weight of C and 67% by weight of Cstraight-chain alkyl methacrylates. Lorol methacrylates are a mixture ofthe following weight percent /2: 3%, C10; C12; C14; C16 and 2%, C15straight-chain a-lkyl methacrylates.

EXAMPLE 22 In this example propionaldehyde is polymerized using Ti[N(CHcatalyst of the invention. The flask is prepared as in Example 17. Tothe flask is added 5 ml. of purified and water-free propionaldehyde andthe temperature is adjusted to -76 C. Then 0.11 ml. of catalyst is addedto the flask dropwise with stirring over a three hour period. After anadditional 4 hours of reaction the excess aldehyde is removed byevaporation at 15 C. The polymer yield is 20%. Part of the poly-mer issoluble in methyl alcohol and has an intrinsic viscosity of 0.05. Thepart of the polymer which is insoluble in methyl alcohol has a softeningpoint above 80 C. A control experiment without catalyst yields nopolymer. Ti(NR is a strong catalyst for bringing about thepolymerization of propionaldehyde. Polymerization takes place over thetemperature range of to 150 C. with the preferred range being --76 to+20 C. The products made at low temperatures are solids while those madeat the higher temperatures are viscous greases. The addition of catalystto the monomer and high monomer concentration gives rubbery products ofsoftening point above 60. Inverse addition yields greases.Polymerization occurs through the C- O bond since the polymer IRspectrum indicates the presence of ethers. The greases are of highmolecular weight ([1;]=0.3). The solids are insoluble even in boilingsolvents, which may indicate crystallinity. In addition topropionaldehyde of course other aldehydes can be polymerized by thecatalysts of the invention, e.g. formaldehyde, acetaldehyde, chloral,glyoxal, butyraldehyde, isobutyraldehyde, n -valeraldehyde, isovaleraldehyde, n-caproaldehyde, nheptaldehyde, stearaldehyde, benzaldehyde,acrolein, crotona-ldehyde, furfural, etc. Also carbon monoxide can bepolymerized or polymerized with other monomers such as olefinichydrocarbons like ethylene, propylene, isobutylene, etc. using catalystsof the invention. Similarly to aldehydes, of course, ketones such asacetone, methyl ethyl ketone, stearone, etc., canbe polymerized by thecatalysts of the invention. Preferred aldehydes and ketones are thealkyl aldehydes and ketones having not more than 18 carbon atoms peralkyl group.

EXAMPLE 23 This example describes the polymerization of vinyl isobutylether using the TiCl [N-(CH catalyst of the invention. 1T he reactionflask is prepared as in Example 17. To this flask is added 10 ml. of thevinyl ether along with 5 ml. of dimethoxyethane. All reagents arecarefully purified and freed of water. To the flask 10 ml. of a catalystsolution containing 0.25 g. of catalyst in 10 ml. of dimethoxyethane isadded over a 3 hour period. The reaction temperature is maintained at 0C. with continuous stirring. After 13 hours, 2.5 ml. of a 4% by weightsolution of tertiary butyl catechol is added and the excess solvent andmonomer are removed by evaporation at 10 C. The conversion to polymer is6%. This polymer is soluble in methanol, has an intrinsic viscosity of0.5 and a melting point of 220 C. The control experiment withoutcatalyst yields no polymer.

EXAMPLE 24 Bis-(diethylamido)-vanadium (IV) oxide anddiethylamide-vanadium (III) oxide 4.2 g. oftris-(dirnethylamido)-vanadium (V) oxide are heated in vacuo. At 100 C.a vigorous gas development starts in the red liquid. Decomposition ofthe vanadiumamide is terminated after half an hour at 140 C. In the trapcooled by liquid nitrogen is trapped one gram of an equimolar mixture ofdiethylamine and N-ethyl-ethyleneimine (detectable by titration withhydrochloric acid and titration of the acetaldehyde produced throughhydrolysis). The solid residue consists of bis (diethylamido)-vanadium(IV) oxide. Yield: 3.1 g. (quantitative). A potentiometric titration ofthe vanadium shows that it is tetravalent in this amide. When thestarting amide g.) for two hours is heated to 210 C., anotherdiethylamide group is split off While forming trivalent vanadiumamide.Yield: 2.4 g. (nearly quantitative).

Analysis.Found: V, 36.6%. Calculated on The low valence vanadium amidesare solid compounds, glossy from dark-violet to black. They areinsoluble in benzol, and soluble in pyridine.

Amide derivatives of transition metals and -oxides are weak catalystsfor vinyl isobutyl ether polymerization. The catalytic strength havingthe order Lower temperatures seem to be more favorable than highertemperatures for the polymerization. The polymer is of high molecularweight ([1;]=0.5), but still soluble in methanol. Of course homologousvinyl ethers to vinyl isobutyl ether are also polymerizable by thecatalysts of the invention, such as vinyl methyl ether, vinyl ethylether, vinyl n-butyl ether, vinyl t-butyl ether, vinyl n-octyl ether,vinyl Z-ethylhexyl ether, vinyl n-decyl ether, vinyl lauryl ether, vinyloxo-tridecyl ether, vinyl Lorol ethers, vinyl tallow ethers, etc. Thevinyl Lorol ethers are a mixture of vinyl straight-chain alkyl ethershaving the following weight percents: 3%, C 61%, C 23%, C 11%, C and 2%,C straight-chain alkyl groups. The vinyl tallow ethers are a mixture ofvinyl straight-chain-alkyl ethers having about 33% by weight of C and67% by weight of C straight-chain alkyl groups. Preferred ethers havenot more than 18 carbon atoms in the alkyl groups.

The transition metal compounds of the invention are especially useful aspolymerization catalysts per se or as transition metal compoundcomponents of catalysts such as the well-known Ziegler catalysts or withother catalysts such as triorgano-phosphines. Normally, the phosphinesused will be trialkyl phosphines having not more than 18 carbon atomsper alkyl group, preferably not more than 8 carbon atoms per alkylgroup. The transition metal compounds of the invention are laso usefulas auxiliary products for textiles, coating and insulating material andthe like. In mixtures with other types of catalyst components, thetransition metal compounds are preferably present in amounts of at least10 mol percent based on the mixture. Nor only can the catalysts of theinvention be used for polymerizing a-olefins such as ethylene,propylene, isobutylene, styrene, a-methyl styrene, octene-l, dodecene-l,etc.; but as seen from the examples above they can also be used forpolymerizing methacrylates, acrylonitriles, aldehydes, vinyl ethers andthe like. The transition metal compounds of the invention are alsocatalysts for a great variety of other olefinic compounds and monomers,such as: vinyl chloride, vinylidene chloride, vinylidene chlorofluoride,vinyloxyethanol, N-vinyl-2-pyrrolidone, vinyl acetate, vinyl pyridine,vinyl propionate, maleic anhydride, fumaric esters, oxides, lactones,lactams, cyclic ethers, cyclic thioethers, cyclic anhydrides, andpolymers of mixtures of these monomers. These named monomers are merelyillustrative of monomers which can be polymerized and not intended to belimiting thereof, and in general a-olefinic compounds can be polymerizedper se or mixed with other olefinic compounds by the catalysts of theinvention. The new catalysts are useful in place of conventionalcatalysts for polymerizing the monomers using conventional polymerizingtemperatures and in the case of many monomers lower than normalpolymerizing temperatures can be used as well as normal temperatures.

Although the invention has been described in terms oispecifiedembodiments which are set forth in considerable detail, it should beunderstood that this is by way of illustration only and that theinvention is not necessarily limited thereto, since alternativeembodiments and operating techniques will become apparent to thoseskilled in the art in view of the disclosure. For example, the termhydrocarbon radicals has been used in its broader sense, in that thehydrocarbon radicals of the reactants and transition metal compoundproducts can also contain constituents other than carbon and hydrogenwhich are nonreactive or at least Which do not interfere to more than adegree and can even promote the desired reaction by which the productsare formed or the use of the products as polymerization catalysts orotherwise; examples of substitutive groups which can be present arenitro, fluoro, chloro, nitrile, etc. One skilled in the art willrecognize that a hydrocarbon radical containing a non-interfering groupis the equivalent of the corresponding hydrocarbon radical containingonly carbon and hydrogen. Accordingly, modificaitons are contemplatedwhich can be made without departing from the spirit of the describedinvention.

What is claimed is:

1. In a process for catalytically polymerizing compounds, the new andimproved catalysts comprising transition metal compounds of the formulawherein R R and R taken singly are hydrocarbon radicals having not morethan 8 carbon atoms, M is selected from the class consisting of titaniumand vanadium transition metals and metal oxides, X is a halogen, a is atleast 1 and is an integer, b, c and d are selected from O and integersbut not more than one is an integer in a compound, when M is tetravalenttitanium one of b, c and d is an integer, and a+b+c+d equals the valenceof M.

2. A process of claim 1 wherein said compounds are acrylonitrile.

3. A process of claim 1 wherein said compounds are alkyl methacrylates.

4. A process of claim 1 wherein said compounds are aldehydes.

5. A process of claim 1 wherein said compounds are vinyl ethers.

6. A process of claim 1 wherein said catalysts are a mixture oftransition metal compounds and a triorganophosphine.

7. A process of claim 1 wherein said compounds are acrylonitrile, c andd are 0, a+b=4, M is titanium, and R R and R are alkyl radicals havingnot more than 8 carbon atoms.

8. A process of claim 1 wherein said compounds are acrylonitrile, b, cand d are 0, a=4, M is titanium, and R and R are alkyl radicals havingnot more than 8 carbon atoms.

9. A process of claim 1 wherein said compounds are acrylonitrile, b, cand d are 0, a=3, M is V0, and R 1 5 and R are alkyl radicals having notmore than 8 carbon atoms.

10. A process of claim 1 wherein said compounds are alkyl mcthacrylates,b, c and d are 0, a:4, M is titanium, and R and R are alkyl radicalshaving not more than 8 carbon atoms.

11. A process of claim 1 wherein said compounds are alkyl methacrylates,c and d are 0, a+b=4, M is titanium,.and R R and R are alkyl radicalshaving not more than 8 carbon atoms.

12. A process of claim 1 wherein said compounds are alkyl methacrylates,b, c and d are 0, 12:3, M is VO, R

and R are alkyl radicals having not more than 8 carbon atoms.

1 6 References (Zited OTHER REFERENCES Chemical Abscracts, vol. 54, N0.14 (July 25, 1960).

WILLIAM H. SHORT, Primary Examiner.

L. M. PHYNES, Assistant Examiner.

